of twenty assigned to temporary duty on board LST-762 at Enewetak between 27 March and 15 April. They were probably on temporary duty for YAG decontamination. Task Unit 7.3.5 (Utility Unit) The Utility Unit consisted of two salvage lifting vessels, the USS Gypsy and the USS Mender, and five fleet tugs, USS Apache, USS Cocopa, USS Molala, USS Sioux, and USS Tawakoni. The Mender replaced the Gypsy on 25 March 1954, when the Gypsy left for Pearl Harbor. Tables 70 through 76 summarize each ship's activity on a shot-by-shot basis. The basic assignment of the Utility Unit was to provide harbor and towing services to the joint task force. The unit also gave extensive support to a number of scientific projects. The Sioux and the Apache Planted fallout collection buoys prior to all shots except KOON for Proj- ect 2.5a and retrieved the buoys after the shots. The Gypsy, Mender, and all the tugs except the Molala assisted Project 1.4 in a variety of ways, but the primary support tug was the Cocopa. During all shots except KOON and NECTAR, the Molala and the Tawakoni assisted Projects 6.4 and 6.5 by prepositioning the YAGs in the predicted fallout area and retrieving them after the shot. All these activities required the Utility Unit ships to operate in waters that had been contaminated by one or more shots. The Cocopa was with- drawn from support of Project 1.4 after UNION and before YANKEE because of a buildup of background radiation in the tug from radioactive silt retained in her seawater piping; she was replaced in that activity by the Tawakoni (Reference 45). The sources of the radioactive silt were the new craters formed at Bikini by BRAVO and UNION. A number of ships also were contaminated by fallout from BRAVO: Gypsy, Cocopa, Apache, and Sioux (Table 21). the The Gypsy in particuiar was most difficult to decontaminate because of corrosion on the decks, which tended to retain fallout. Furthermore, all ships of the Utility Unit 355